Lakhmir Singh & Manjit Kaur: Stars and the Solar System- 1 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.1. Name any two celestial objects which we can see easily in the night sky.

Moon and the stars are the celestial objects which we can see easily in the night sky.

Q.2. Name the star (after the Sun) which is closest to the Earth.

Alpha Centauri is the star which is closest to the Earth after the Sun. It is at a distance of about 40,000,000,000,000 km from the Earth.

Q.3. Name the star which remains fixed at the same place in the sky in the North.

The pole star is the star which remains fixed at the same place in the sky in the North.

Q.4. Name the unit which is used to express distances between the various celestial bodies (like stars and planets).

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year. The speed of light is 300,000 km per second. For example, the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. The distance of the Sun from the Earth may be said to be about 8 light minutes.

Q.5. Why is the distance between stars and planets expressed in light years?

The distance between the Earth and stars and the distance between the stars is very large. The stars are millions of times farther away than the Sun. the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years. For example, the distance of the Sun from the Earth may be said to be about 8 light minutes.

Q.6. What do you understand by the statement that a star is 8 light years away from the Earth?

The distance between the Earth and stars and the distance between the stars is very large. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years.
1 light year= 9.46 × 1012 Km. Now, a star is 8 light years away from the Earth. It means the distance between the star and the Earth is equal to the distance travelled by light in eight years.
Therefore, the star is located 8 × 9.46 × 1012 Km = 75.68 × 1012 Km away from the Earth.

Q.7. Name the constellation which reminds us of a large ladle or a question mark in the night sky.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

Q.8. In which season of the year is the constellation Orion visible in the sky?

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

Q.9. In which season of the year is the constellation Ursa Major visible in the sky?

Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.

Q.10. Give two other names of Ursa Major constellation.

Ursa Major constellation is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

Q.11. In which season of the year are the following constellations visible in the night sky?
(a) Cassiopeia
(b) Leo Major

(a) Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.
(b) Leo Major is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle. You can use the Pointer stars of the Big Dipper to find Leo Major.

Q.12. Name the biggest planet of the Solar System.

Jupiter is the biggest planet of the Solar system. It is so large that about 1300 earths can be placed inside this giant planet.

Q.13. Name the smallest planet of the Solar System.

Mercury is the smallest planet of the Solar system. It is nearest to the Sun.

Q.14. Which force keeps the members of the Solar System bound to the Sun?

The Sun and the celestial bodies which revolve around it form the solar system. It consists of large number of bodies such as planets, comets, asteroids and meteors. The Gravitational force keeps the members of the Solar System bound to the Sun.

Q.15. Why does the Sun appear to be bigger and brighter than all other stars?

The Sun is the nearest star which is continuously emitting huge amount of heat and light. Hence, the Sun appears to be bigger and brighter than all the planets. The Sun is the source of almost all the energy on the Earth.

Q.16. Which is the main source of heat and light energy for all the members of the Solar System (like planet and satellites, etc.)?

The Sun is the nearest star which is continuously emitting huge amount of heat and light. The Sun is the source of almost all the energy on the Earth.

Q.17. Name a star having a system of planets with life on one of its planets.

The Sun is the star having a system of planets with one planet called Earth with life on it. The Earth is the only planet on the solar system on which the life is known to exist.

Q.18. Name the planet having a well-developed system of rings around it.

Saturn is the planet having a well-developed system of rings around it. These rings are not visible with the naked eye. They can be observed with a small telescope.

Q.19. Name the planets which lie between the Sun and the Earth.

Mercury and Venus are the planets which lie between the Sun and the Earth. Mercury is the smallest planet and is very close to the Sun. Venus is the nearest planet to the Earth and is the brightest planet of the Solar System.

Q.20. How will our Earth look when seen from a space-ship or Moon?

When seen from a space-ship or Moon, the Earth appears blue-green in colour. It is due to the reflection of light from the water and landmass on its surface.

Q.21. Name the planet
(a) nearest to the Sun, and
(b) farthest from the Sun.

(a) Mercury is the planet nearest to the Sun. It is the smallest planet of our Solar System.
(b) Neptune is the farthest planet from the Sun. It is the fourth largest planet in the Solar System.

Q.22. Name two planets which have been discovered with the help of telescope.

Uranus and Neptune have been discovered with the help of telescope. These are the outermost planets of the solar system. They can be seen only with the help of large telescopes

Q.23. Name the hottest planet.

Venus is the hottest planet of the solar system. It is the second planet from the Sun and has a temperature that is maintained at 462 degrees Celsius.

Q.25. Name two planets which show phases like the Moon.

Mercury and Venus shows phases like the Moon. They have the orbits which are smaller than the Earth and exhibit the full range of phases like the moon.

Q.25. Name one planet of the Solar System having life on it.

Earth is the only planet of the Solar System having life on it. The special environment conditions are responsible for the existence and the continuation of life on the Earth. These conditions include the right distance from the Sun, so it has the right temperature, the presence of water, suitable atmosphere and a blanket of ozone.

Q.26. Which characteristics of Mars distinguishes it from other planets?

Mars appears slightly reddish in colour and is also called the red planet. It has two small natural satellites.

Q.27. Which planet is known as the red planet?

Mars is known as the red planet. It appears slightly reddish in colour due to the presence of iron oxide on its surface.

Q.28. In which part of the sky can you find Venus if it is visible as an Evening Star?

Venus appears in the eastern sky before sunrise. It is known as morning star. Sometimes, it appears in the western sky just after sunset. It is known as Evening star.

Q.29. Which characteristic of the planet Saturn makes it unique in the Solar System?

Saturn has rings around it which makes it unique in the Solar System. These rings can be observed with a small telescope and cannot be seen with the naked eye. Saturn also has a large number of satellites.

Q.30. Name two planets which can be seen as ‘Morning Star’ and ‘Evening Star’.

Mercury and Venus can be seen as ‘Morning Star’ and ‘Evening Star’.

Q.31. What name is given to the celestial body which revolves around a planet?

The celestial body which revolves around a planet is known as a Satellite. Moon is a natural satellite of the Earth.

Q.32. Which two planets have asteroids between them?

Mars and Jupiter have asteroids between them. These planets have a large gap between the orbits. This gap is occupied by a large number of small objects that revolve around the Sun called the asteroids.

Q.33. Name two objects other than planets which are members of the Solar System?

Asteroids and Comets are the two objects other than planets which are members of the Solar System.

Q.34. Name the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail.

Comets are the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun.

Q.35. Which celestial body is seen as a bright streak of light coming down the night sky?

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth’s atmosphere.